/**
 * 泛型
 */
function join<T, P>(first: T, second: P) {
  return `${first}${second}`;
}

function anotherJoin<T, P>(first: T, second: P): T {
  return first;
}
function map<T>(params: T[]) {
  return params;
}

console.log(map<string>(['1','2']))